People from the Outer Hebrides are among those with the highest risk of developing a genetic disease that causes a dangerous build-up of iron in the body, a study suggests.
The study marks the first time the genetic risk for haemochromatosis has been mapped across the UK and Ireland, despite a high incidence of the condition among Scottish and Irish populations.
Targeting genetic screening for the condition to priority areas could help identify at-risk individuals earlier and avoid future health complications, experts say.
Haemochromatosis symptoms can evolve over decades as high iron levels in the body cause damage to organs. Early diagnosis and treatment, such as regular blood donation to reduce iron levels, is key to prevent liver damage, liver cancer and arthritis.
The condition is caused by small changes in DNA, known as genetic variants, which can be passed down through families. The most important risk factor in the UK and Ireland is a genetic variant called C282Y.
Scientists at the University of Edinburgh analysed genetic data from more than 400,000 individuals in the UK BioBank and Viking genes studies to determine the prevalence of the C282Y variant across 29 regions of the British Isles and Ireland.
They found that people with ancestry from the north-west of Ireland have the highest risk of developing haemochromatosis, with one in 54 people estimated to carry the genetic variant.
This is followed by people from the Outer Hebrides (one in 62) and those from Northern Ireland (one in 71).
Mainland Scots, particularly in Glasgow and southwest Scotland, are also at increased risk of the condition, with one in 117 people estimated to carry the variant.
The high combined genetic risk across these locations suggests that focusing genetic screening at these key areas would discover the largest number of people with the condition, researchers say.
Professor Jim Flett Wilson, Chair of Human Genetics at the University of Edinburgh, said: “If untreated, the iron-overload disease haemochromatosis can lead to liver cancer, arthritis and other poor outcomes.
“We have shown that the risk in the Outer Hebrides and Northern Ireland is much higher than previously thought, with about one in every 60 people at risk, about half of whom will develop the disease.
“Early detection prevents most of the adverse consequences and a simple treatment – giving blood – is available. The time has come to plan for community-wide genetic screening in these high-risk areas, to identify as many people as possible whose genes mean they are at high risk of this preventable illness.”
The study was funded by the charity Haemochromatosis-UK and is now published in the journal, Nature Communications.
